Chen Lin is a weapons manufacturer based in Columbia's Finkton area. Despite an ethnic background that subjects him to the racist views of most of Columbia, Chen Lin is quite successful and has opened up a weapons shop.

Booker DeWitt and Elizabeth must visit Chen Lin in order to gain weapons for Daisy Fitzroy and the Vox Populi, who have seized control of Booker and Elizabeth's airship, The First Lady.

Upon arrival at the shop, the two discover that Chen Lin is missing, and a talk with his wife reveals that he went off in search of his tools, which were taken for unknown reasons. Booker and Elizabeth also notice a shrine dedicated to Buddha halfway up the stairs to his workshop.

The two then battle through Columbia with the aim of finding Chen Lin, eventually locating him in an underground prison cell. Unfortunately, the gunsmith has been beaten to death, but here Elizabeth first reveals she can use her powers to open "tears" and travel between different universes, and the two then travel to an alternate version of Columbia where Chen Lin is alive.

Upon returning to the weapons shop Booker and Elizabeth then discover that Chen Lin is still alive, the Buddha shrine has transformer into one honoring Comstock, and that Chen Lin's wife has changed in appearance and race.

They also find that Chen Lin is seemingly stuck in a limbo between two worlds, conflicted because he died in one, but is alive in the other. Booker and Elizabeth then deduce that he is still searching for his tools, and go off to track them down.